Centrifugal blasting machine



Marcb IQ, 1942. c UNGER 2275,479

CENTRIFUGAL BLAS'I'ING MACHINE Filed Das. 14, 1939 3 Sheets-Sheet l c.E. UNGER CENTRIFUGAL BLASTING MACHINE March 10, 1942.

3 Sheets-Sheet. 2

Filed Dec. 14, 1939 INVENTOR (hesier M 1942- c. E. UNGER 2275479CENTRIFUGAL BLASTING MACHINE Filed Deo. 14, 1939 s Sheet-Sheet sIII/III,

NVENTOR lhisier ggfer BY Ma/! a;

4.' ATTORNEY Patenten] Man. 10, 1942 7 UNITED STATES PATENT OFFICE TheAmerican Foundry Mishawaka,

Equipment Companm Ind., a corporation o! Delaware Application Decbmber14, 1939, Seria.l N0. 309,179

16 Claims.

This invention relates to centrifugal blasting machines, andmoreparticularly to an irfrproved blasting machine capable of centrifugallyimpelling abrasive ab blasting velocities concentrated in the desiredwork Zone.

In the cleaning of metal castings, forgings, Iarge sheets and the like,il; is desirable that the thrown abrasive be concentrated not only as todirection but so controlled as to define an impingement pattern of thedesired length and breadth through which the abrasive is substan--tial1y uniformly distributed. The centrifugal blasting machine formingthe subject matter of this invention is designed to attain thesedesirab1e ends.

In accordance with this irivention, an abrasive throwing roter isprovided which is driven in timed relation to a control runnerpositioned within the roter. The roter comprises generally a roter headmounted upon a high speed shaft having an abrasive receiving containerfixed 130- rotate thereon.: The container is formed of suitable strongwear resistant metal, having a rear wall and a tubular side wall, theinterior surface of which provides a support for the abrasive suppliedthereto. Abrasive is supplied 110 the rotor container by means of acontrol runner positioned therein. The interior of the roter containeris provided with a plurality of spaced ribs or vanes fixed 130 rotatewith the container. The abraslve, driven by centrifugal force out-'wardly against the interior 'surface of the tubular side wall of thecontainer, drifts against the ribs'or vanes therein provided and iscarried around the interior surfac of the container during rotationthereof.

The interior surface of the Container is provided with uniformly spaceddischarge ports in the tubular side wall the'reof. When the abrasivecaught by the vanes or ribs has pi1ed up to a point where its angle ofrepose is exceeded, the abrasive will string laterally from each lug 01'vane, forming a ridge of abrasive between the discharge ports in thecontainer.

The control runner is also provided with an 45 abrasive receivingcontainer having a rear wall and a tubular side wall fixed to a driveshaft which may extend through the hollow shaft of the rotor. Thecontrol Container is supplied with abrasive by means of a suitableabrasive supp1y pipe which is feol into the interior thereof. Theabrasive is discharged rhrough spaced discharge ports provided in theside wall cf the control container during rotation thereof, collects ordri fts against the vanes or ribs provided on the 5 interior surface ofthe roter container, and thence strings across the side wall of theroter container in transversely extending drifts or ridges.

An important feature of this invention is the provision of a pluralityof scraper vanes which are fixed 120 rotate with the runner container.The unter ends of these scraper vanes rotate over the strings or ridgescf abrasiv positioned between the discharge ports of the roter containerand scrape the top portion of each abrasive ridge into the dischargeports 01' the roter. The outer ends of the scraper vanes preferably havea broad edge which extends on a bi'as with respect 120 the axis ofrotation of the contml runner.

As thus shaped the scraper vanes of the control runner operate 130scrape abrasiv through the discharge ports in the roter substantiallythe full width thereof, thus obtaining an impinge'- ment pattern of thedesired width. The throwing roter may be provided with abrasivepropelling blades associated with the discharge ports thereof to givethe abrasive a positively impelled blasting vel0city.

The number of scraper vanes provided on the control runner should beeither greater or less than, but not equal to, the number of dischargeports provided in the throwing roter. Where it is desired to obtaindirectional discharge over one section of the roter only, the number ofscraper vanes provided on the c0ntrol runner is preferably either oneless or one more than the number of blades or discharge passagesprovided in the throwing roter.

The roter shaft and runner shaft are operably connected by means 'of asuitable drive trans mission so that a drive ratio between these twoshafts is established which is in inverse ratio to the number of scrapervanes provided on the control runner and discharge passages provided inthe throwing roter. Assuming, f0r example, that. the rotor is providedwith eight throwing blades or discharge passages and the runner isprovided with nine scraper vanes, and assuming further that an effectiveblasting speed can be attained with this machine when the rotor isrota'ted at 2250 R. P. M., then the runner should be rotated at 2000 R.P. M. If this inverse ratio is at all times maintained, the scrapervanes in the runner can be moved into position 120 scrape the abrasiveinto the disch'arge passages of the rotor at any predetermined clockdialposition, so

that 'the machine will flre the abrxsive over a predetermined clockdialsector during 'rotation thereof. When it is desired to discharge thebrasive from two' diametrically opposed rt secto rs simultaneously, thescraper vanes in the control runner are preferably either two iess ortwo more than the number of discharge passages in the throwing rotor sothai; the scraper vanes in the control runner anal the dischafgepassages in the throwing roter will move into discharging alignment abtwo positions, diametrically spaced. The necessary flxed drive ratiobetween the roter shai't and runner shaft can be maintained by positiveinterconneoting drives between the shafts und rotating both shafts froma common power source. The drive transmission between the rotor shafta.nd runner shaft may take the form of intermeshing gears, chain -ancisprocket drive, Morse drive, or.any other positive drive mechanism whichwill maintain the required drive ratio.

which surfaces may Ioe provided by removable blades. The blades or-discharge passages or ports in the roter may be made of almosi; unydesired radial Iength and 'almosi: a.ny desired number thereof may beprovided, ranging from one to sixteen or more. Substantially the oniyessential criterion that musi: be followed is tlxat the scraper vanes inthe control runner must be either m'ore or lass than the number ofdischarge ports or blades inthe throwing roter andfurther, ihat therunner end rotor must be driven in substantially positive timed relationso that the abrasive scraper vanes in the runner will advance ahead ordrop back of the discharge ports or passages in the r0tor ai; apredetermined ciockdial position during timed rotation therebf so thatthe encls of the scraper vanes will pass over the discharge ports inthe' roter a.t the desired predetermined clockdial' position to scra.pethe ridged abrasive thereinto.

Directional control adjustxnents can be eifected by readjusting theposition of the runner on its drive shaft, by readjusting the positionof the rotor on ii;s drive shaft, by readjusting the sprocket, gears orother positive drive mecha-' nism .that operably connect the runnershaft with the roter shaft.

1 An object 01 this invention is to provide a. centrifugal blastingmachine in which directional firing of the thrown abrasive can besubstantialiy controlled so as to produce a blast pattern on the targei:of substantially any desired width und length, which pattern ischaracterized by Uniformity in blast over the entire surface thereof.

Other objects and advantaes o1 this invention will become apparent asthe disclosure proceeds. The invention also consists in certain new undoriginal features of construction and combinat-ion of Parts hereinaftersei: forth und claimed. Althoiigh the novel features which are believedto be characteristic o1 this invention will be particularly pointed outin the 'claims appended hereto, the invention itself a.sbo its objectsund advantages, and the manner in which ii: may be carried out, may bebetter understood by referring to the following description taken innonnection with rbhe accompanying drawings formirlg a part thereoi, inwhich Fig. 1 is a transverse cross-sectional view through the abrasivethrowing machine, showing the throwing roter und control runner withdrives therefor;

Fig: 2 is a tront face view of the throwing rotor end contr ol runner asiI; anpears when looking in the direction 01 the arrows 2-2 01 Fig. 1;

Fig. 2a is an enlarged sectional view through a portion 01 the throwingrotor taken along line 2a-2a o1 Fig. 2;

Fig. 3 is a cross-sectional view through the throwing roter und controlrunner as ii: appears when looking in the direction of the arrows 3--3of Fig. 1;

Fig. 4 is a cross-sectional view showing certain details of the drivingmechanism for the throwim; roter a.nd control runner this view bei ngtaken along line oif Fig. 1;

. 'Fig. 5 is a transverse cross-seotional view through an abrasivethrowing machine showing a blacled throwing rotor and control runner of'somewhat modified construction; end

Fig. 6 is a cross-sectionalview through the throwing roter and controlrunner as it appears when looking in the direction of arrows 6-0 o! Fig.5.

Similar reference characters refer 'to similar parts throughoyt thes'everal view's of thedrawings am! the specification, 4 1

Referring more particularly to Figs. 1 to 4 inclusiye, a throwing rot0rIII is illustrated fixed to a hollow shaft I3.rotated by a. pulleyS0operably connected to a suitable source of power as an eiectric motor,es by a V-belt drive. A nontrol runner 00 mounted upon a shaft EIextending through hollow shaa.fisv I3 is operably connected to be drivenin timed relation to shaft I3 and rot0r I0. The throwing rotor I0 ismovided with runner 40 with respect to the throwing roter I0 is suchthat i:he scraper vanes 08 o! the control runner will scrape the ridgeor dritt o! abrasive into the discharge ports 21 of the rotor when thescraper vanes 48 move thereover in the desired clockdial positi0n so asI:o efieci: controlled directional flring of the abrasive ejected tromthe throwing roter III.

The throwing roter I0, as shown in F'igs. 1 to 3 inclusive. may comprisea rotor head constructed in the torm o! a. container ha.ving a. rearwall II and a tubular side wall I2 which may be formed as a Singlecasting from a suitable tough wem resistant metal. The real Wall v II013 the container may be provided with a cantral opening IG whichreceives i'.he closed end of another tubular container 4I which forma apart of the control runner I0. The rear Wall II oi the throwing roter I0is fixed to a hollow shaift I3 by means of a hub member II which isflxed to I;he shaft I3 by means cf aspline or sei: screw and which isalso flxed to the,reb.r Wall II ot the contafiner roter I0 bysuitablebolts I5. The interior of the roter container I0 may be provided with anabrasive resistant lining, 11 desired, comllnes the rear wall II of thecontainer I am} a side wall lining surface 23 which lines the ins1deface o! the tubular side wall I2 0x the container I0. The interior sidewa1l surface 23 of the container I0 is preferably cf su'bstantial depth,the inner half of which is provided with a plurality of Spaced vanes 22,equal in number to the discharge ports 21. The vanes or Iugs 22 areflxed to rotate with the roter container I0, and each '26 of thecontainer I0.

It will be noted that drift formin g vanes 22 equal in number I:o thedischarge ports 21 are provided.- Each vane 22 has its lower pocketforming end positioned approximately midway between adjacent; spacedopenings 21 so that the abrasive put in motion by each vane 22 will rollin the form of a dritt between adjacent spaced dis charge ports 21 wherethe drift will normally cling to the inner surface 26 of the container.An abutment member positioned adjacent the unter free edge of thecontainer side wall I2 may be provided to prevent abrasive fro'mspilling over the free edge of the container side wal1. The abutmentmember 20 may'be in the form of a ring having a cen tra.l openingthrough which the discharge end of the abrasive supply COU- duitextends, the ri'ng seating within a pocket '2I and held in positionthereby.

The control runnr 40 provides means for supplying abrasive to the driftforming vanes 22 cf the rotor container I0 and for scraping the driftedabrasive into the discharge ports 21 0f the rotor I0 during apredetermined selected clockdial sectcr of rotation thereof whereby theabrasive thrown by the rotor I0 is directionally controlled. An abrasivesupply container 4I having a tubular side wall 42 and a man wall 43extends into the roter cont'ainer I0 and is fixedly securea to the endof runner drive shaft 5I. The runner drive shaft 5I may be provided witha square o! rectangular boss 52. at one end thereof which extendsthrough a square opening 53 in the rear wall 43 of the feeding container4I. A clamp- Ing platze 54 which bears against the inside face of therear wall 43 of the feeding container 4I receives a lock holt whichscrews inco the threaded end of the boss 52 of shaft 5I. thus fixedlys1curing the feeding container 4I thereto.

Abrasive is supplied to the feed container 4I by means of a feed pipe 45having the discharge end 45 thereof arranged to deposit abrasive intothe rotatably mounted feed container 4I. The feed container4l may beprovided with an inturned lip 44 which surrounds the discharge end 45 ofthe feed pipe to prevent leakage of abrasive therefrom. The feed pipe 45may alsq be provided with a circumferential flange 41 which overlaps theinturned lip portion 44 of the feed- Ing co'ntainer 4I. II; will beappreciated that the feeding cont-ainer 4I must be free to rotatewithout interference with the feed pipe 45, sufficient clearance betweenadjacent stationary and rotating parts being accordingly provi ded.

The abrasive a rolls down the feed pipe 45 and into the feeding'containeir 4I where it clings in the form of a'blanket; around theinterior face; of the tubular side wall 42 thereof. A plurality ofspaced discharge ports 46 is procled in the I:ubular side wall 42 cf thefeeding container 4I, through which the abrasive is discharged into thepath of rotat-ion of the dritt forming vanes or lugs 22. Preferably theinner ends cf the vanes 22 extend close to the unter periphery of thetubular side wa1l 42 0f the feeding container 4I. Discharge pdrts 46'.equal in number to the dritt forming vanes 22, are preferably provided.The discharge ports 46' preferably have an axial width 1ess than thewidth of the drift member 3I fixed to the vanes 22. The side Wall member3I has a central opening 32 provided therein into w hich the feedingcontainer 4I projects. The outer periphery 33 of the circular plate 3Iterminates short of the side wall linear 23 to permit lateral drift ofthe abrasive thereunder. The side wall member 3I may be integrallyformed with the drift forming vanes. 22

01' rnay be bolted 01 otherwise securcad 1:0 the rear wall II of therotor. The circular' side wall plate 3I .serves to retain the abrasiveon the advancing face 24 of the drift forxning vanes 22, gu1'ding theabrasive into the pockets 25.

The control runner 40 is providecl with a plurality cf equally spacedscraper vanes 48 which extend laterally from and may be integrallyformed with the tubula.r side Wall 42 of the feeding container. Thescraper vanes 43 are for wardly inclined with respect to the directionof rotation cf the roter, as Shown more particularly in Fig. 2, when thecontrol runner 40 is provided with a. greater number of scraper vanes 48than discharge passages 21 in the rotor. I1 the Control runner 40 isprovided with a less number of scraper vanes 48 than the number ofdischarge passages 21 in the throwing rotor I0, the vanes 48 would thenbe inclined rearwardlj with respect the direction of rolsation thereof.In theembrzdiment illustrated in the drawings, the cantrol runner 40 asshown is provided with nine scraper vanes 48 while the throwing *otor I0is provided with eight discharge ports 21. II; will also be noted thatthe lower end 49 of each of the scraper vanes 48 is positioned closelyadiacent the inside surface. 26 of the tubulax wall I2 of the roter I0and has its outer end 51 biased with respect to the axis of rotatirn ofthe control runner.

T0 guide the abrasive over the inclined surface 26 in a well definedridge er string. one or more abrasive retaining grooves 26', as shown inFigs.

2 and 2a, may be provid-ed fnr each dritt forming vane. These groovespreterably extend on a. bias and approximately parallel In the biasedends 49 of the scraper vanes 48. The arccv.es 26 providea firm grip forthe abrasive so that the abrasive will pi1e up thereover in a welldefined rid=r e which will be ensra&zed by the lower ends 49 of thescra.per vanes 48 during operation The hollcw rotor supmrting shaft I3extends into the hub I4 and is supported by a pair 0f suitable spacedbrackets 66 and 61 'each having one or more ba.ll bearing mountings forthe shaft I3,

raceway collar I2 fixed to shaft 5I, raceway collars "II and I2 havingball bearings 13 rollable therebetween. The opposlte end of shaft 5I maybe likewlse supported by a suitabl bearing comprising raceway co11ar I4flxed to the lnterior of hollow shaft I3 and raceway collar 15 flxed tothe runner shaft 5I wlth roher bearings I in position to roll betwee nthese r'aceway colllars.

Means are provided for operably connectlng rotor shaft I3 to runnershaft I so that they can be driven in the proper timed relationship. Asshown more particularly in Figs. 1 and 4, a driving gear 'I'I is flxedto the end of rotor shaft I0, Which driving gear meshes with a pluralityof transfer gears I8 each fixecl to a spindle sho.ft IQ.

Euch spindleshaft I0 is free to rotate in suitable feedlng contal ner 4Icllngs to the Interlor surface of the tu' bu la' r slde wall 42 therecf,and as more abrasive 15 supplied thereto thls additional abraslve rollsover the top of the lnltial abraslve, first supplied a.nd dlschargesoutthrough the peripherally arranged discharge ports 48'. The abrasivedischarglng from the ports 48 moves radially outward between the drittforming vanes 22 o1 the throwing rotor I0, comes into contact w1th theadvancing face 24 015 the throwlng Ing vanes 22 and lodges in theV-shaped pockets 25 formed by the rearwardly lncllned vanes 22 and theinslde surface 23 01 the rotor contalner. .As additional abra;slve issupplled to the pockets 25, the additional abrasive drifts to the rlghtin the structure shown in Flgs. 1 and 2 and rolls gea.r 85 fixed to theend of runner shaft IiI.. The

gern housing 82 may be provided with asuitable collar 86 by means ofwhich it may be secured as by .set screw 81 to a clrcular fiange 00provide'd on the adjacent shaft supporting bracket 0I. The gear housingenclosing cover 83 may be removably secured' to the gear housing 02 bymeans of sultable lag screws or bolts 09, giving free acces to the tralnof gears ther6in. Thus the driving mechanism for rotor shaft I3 a.ndrunner shafti 5I is completely enclosed, and grease or lubricating oilin the space' 90 withln thahollow shaft- I3 and the space 9I wlthinthegear box caslng 02 is kept in constant agitatlon by the moving parts tolubricate the gears and shaft supporting bearlngs thereln.

It will be appreclated that when the throwlng rotor I0, equipped witheight discharge 'p'orts 2'I, a.s shown in Figs. 1, 2 and 3, 1s rotatedat 2250 R. P. M. and the control runner 40, equipped with nine dischargescraper vanes 48, is rotated at 2000 R. P. M. the sc raper vanes 48 willmove gentlally from the periphery of the rotating v throwing rotor.obtained by making the gears 'I'I and 85, which drive the rotor shaft I3and runner sha.ft 5I, 01 the proper relative tooth ratio to effect thisresult. Since the 'speed differentialbetween the control runner 40 andthe throwlng rotor I0, in the .machine disclosed in Figs. 1 to 3inclusive. inay be only 250 R. P. M. no serious wear' on the adjacentfaces of the moving parts of the control runner 40 and throwing rotor I0results.

When the machine shown in Flgs. 1 to 3 Inclusi ve Is brought up tospeed, with the throwlng rotor I0 rotating at 2250 R. P. M. anrl theoput rol runner 40 rota.tlng a.t 2000 R. P. M. abrasive ls supplied tothe lnterior of the feedimg cantainer 4I. The Initial abraslve suppliedto the This feed differentlal ma.y De

onto the Inclined surface 26 of the rotor con-- talner. Since theabrasive discharglng laterally from the drlft formlng vanes 22 hasalready achievec1 a periphetal velocity substantially equal to therotating ve1odlty of the Inner urface 23 of the rotor container, thisabraslve continues to cling to the lnclined surface 26 of the rotorcoutainer a.nd piles Up in a rldge or drift between a.djacent dischargepassages 2'I. This drifting abrasive when undisturbed will substantiallymalntaln Its drlfted posltion unless excesslve quantltles of abrasive isfed thereto, because o! the grooves 26' or lntermedlate rlbs 26".

It will be noted that the control runner 40 rotates in the samedirection s.s the throwlng rotor I0 but at a predetermlned lesserveloclty. Slnce the control runner 40 Is provlded wlth nine scrapervanes 48 and 1s dr1ven in tlmed relationship to the throwlng rotor I0,a.s above lndlcated. the dlscharge passages 21 of the throwing rotor I0will advance under the ends 40 of the scrapervanes 40 at a,predetermined clockdial position, dependlng upon the setting of thecontrol runner 40 with respect'to the throwlng rotor I0. Ea'ch rldge cfabrasive s treaklng from euch dr1ft form- 1ng vane 22 laterally acrossthe inclined surface 26 of the rotor container is engaged by the rearface 49' of e'ach scraper vane 48, whlch abraslve ls scraped into thedischarge passages 21 advanclng under it. The free ends 40 of thescraper vanes 48. are arranged on a blas, as shown in Flg. 2, so thatabraslve is discharged from the ful1 axial width of the discharge ports21 so that uniform dlstribution of the discharged abraslve is obtained.An impingement pattern of any deslred length may be obtained dependentupon. the peripheral Iength of the dlscharge ports 21 In the rotorcontainer.

The discharge ports.2 'l may be lined or covered by means of a wearresisting 1iner 2I' whlch may be made in the form of a tube. The liners2'I' ma.y be removably held in fixed posltion by a palr of meta1 bands2'I" whlch overlap the lower end oi the weag members 2'I', as shown inFig. 1, und whlch bands may be held in platze hy spaced screws 2'I'. Thering member 20 may be made sectional.in form, as shownin Flg. 1, andnlhy be so formed as to overlap the lnturned fiange4'l on the feed plpeso as to provide a substarxtlally enclosed ohamber within the rotor headI0, thus appreclably lessenlng the effect 6I' a.ir currents.

The batlle member 20 flxed to the rotor contalner prevents lea;kage ofabrasive over the outer r1m of the rotor container. If deslred, thebaflle member 20 may extend substantlally to the outer peflphery of thefee.d plpe 45 andto a position to substantially overla'p the flangeportion 41 of the feed pipe 45, thus lessenlng the efiect ofdistrlbuting alt currents wlthln the rotor I0. The

- inclusive.

throwing faces 21' of the discharge ports 21 can be of any desiredlength and the feeding coutainer 41 and the rotor container may also beof any desired diameter,

A centrifugal abrasive blasting ma-cmne coustructed in accorclance Withthis invention may take other forms than that shown in Fig s. 1 so 3 Forexample, there is shown in Figs. 5 and 6, a centrifugal blasting machineof somewhat modified construction, comprising a throwing rotor 100having a contml runner 150 associated therewith. The throwing 1 01201100 may comprise a side wall member 101 and a side wall member 102spaced therefrom and extending generally parallel to side wall member101, which side wall members may be connected by suitable spacers 103having their reduced ends 104 welded or otherwise secured 130 the sidewall members. Equally spaced radially extending blacles b are removablymounted between the spaced side wall members 101 and 102, each bladecomprising a bottom wall portion 106 and side flange portions 101 whichseat within suitable paired grooves 105 provided on the inside face ofthe side wall members 101 and 102. Each blade b may be removably securedin operative position by means of a suitable set screw 135 havingatapered end which seats within a corresponding taperedmcess pro- Theside wall members 101 and 102 are ea.ch

provided with a circular opening whose peripheral inner edges 108 and109 respective1y are substantially in alignment with the inner ends ofblades b. A tubular sleeve member which forms the 1'otor containerextends lnto the aligned circular openings in the front and rear sidewall members 101 and 1112, respe ctively and is provided with anoutturned flange portion 123 which may be secured as by screws 124 tothe front side wall members 102 so as to rotate with the blades b. Thetubular sleeve member 120 is provided with a tubular side wall 121 and arear wall 122 which seats within a suitable circular cavity 115 in thehub 110. The collar portion 111 of the hub 110 is provided with acircular opening into which the hollow tubular drive shaft 13 extends,the hub 110 being secured to the drive shaft 13 by means of a suitablespline 112. The hub 110 is provided With a securing fiange 113 whichseats wardly of the feed charge ports 125., eight drifb forming vanes128 and eight dischaige ports being illustrated in Figs. 5 and 6. A circular abutment; member 133 fixed the tubulalrside wall 121 of thetubular sleeve member 120 retains the abrasive within the sleeve member120.

A control runner is positioned within the tubular sleeve member 120, asshown in Figs. 5 and 6. The control runner 150 comprises a tubular feedcontainer 151 having a tubular side wall 152 which extends centrallyinto the tubular sleeve member 120. The.rear wall 122 01 the tubularsleeve member 120 has a ciroular opening 134 provided centrally thereinto receive the rear end. of the feed container 151.

tainer I 51 is provided With a rear has a square opening 155 thereinsquared end 154 of the 51 -extends. A top plate 156 overlaps the insideface of the rear wall 122. A threaded holt 151 which extends through thetop plate 156 is screwed into thg squared end 154 of the drive The feedcouwall 153 which into which the shaft 51 to rigidly hold the feedcontainer 151 to the abutment member 133 provided on the roter containerso as to lassen the efiect of disturbing air currents therein. T0prevent clogging of the feed pipe 160, an aperture 164 may be providedin its lower belly adjacent the discharge end for admission of air intothe lower end of the feed pip which ins ures free fiow of abrasivetherethrough. Leakage of abrasive through the air inlet port 164 of thefeed pipe is preVented by a shelf 165 which overhangs the opening 164.

When the machine has been brought up speed, abrasive is supplied to 1:hefeed container 151 by the abrasive supply pipe 160, which abrasive isthrown by centrifugal force aainst the inside surface thereof. Theabrasive works rearcontainer 151 and fiows 01113 through the dischargeports 110 in the tubular against the side wall member 101 and is securedthereto bymeans of suitable bolts 114. The tu bular side wall 121 of thetubular sleeve 120 1s provided with a plurality of discharge openmgs125, each positioned acljacent tlmaaclvancing fa ce of a blade b, theopening 125 having an ax1al width extending between the side flanges 101of its corresponding blade b.

The tubular sleevemember 120 is provided also with a plurality ofspaced, rearwardly inclined' vanes 128 positioned rearwardly of thedischarge ports 125. Bach vane 128 forms with the inner surface 126 ofth tubular sleeve member 120 an abrasive r-eceiving pocket 121. Eachpocket 121 provides a place into which the abrasive sopplied by thetubular sleeve member 120 may dr1ft, the outer end 129 of each vane 128being secured to the inner surface 126 of the tubular sleeve member 120.The outer end 129 of each vane 128 is located approximatelyequidistantly between the adjacen't spac&d disoharge ports 125 butrearwardly thereof. I1; will be noted that the dritt iorming vanes 128are equal in number 1:0 the disvanes 111 side wall thereof and'then intothe path of rotation of the drif1: forming vanes 128. The abrasive flowsover the advancing faces of the vanes 128 into the abrasive receivingpockets 121. As each pocket 121 is supplied with an increasing quantityof abrasive, the excess abrasive thread across 1:he inner surface 121 ofthe feed container in the form of a ridge or pile of abrasive Each ridgeor pile of abrasive will be cleposited betWeen adj'acent discharge ports125 in 1:he tubular sleeve member 120.

The control runner 150 is provided with a plu rality of equally spacedscraper vanes 111 which extend from the side wall 152 of the feedcontainer 151 to a point closely acljacent the inside surface 121 willbe noted in the structure shown in Figs. 5 and 6 that nine soraper vanes111 are supplied which Sh0li1dil'llille forwardly with respect to thedirection of rotation thereof. The scraper may be formed of wearresistant material and may be integrally formed with a tubular side wall152 of the feed container 151.

The tubular drive shaft 13 of the throwing control runner drive shaftwill stre.k orl of the tubular sleeve member 120. It

roter I is driven in timed relatlon to the drive shaft l of the controlrunner by drive mechanlsm which may be of the type illustrated morepartlcularly in Fig. 1. II desired, an 011 seal may be providedcomprising a'gasket-I8l which surrounds the inner endl of the shaft 5I,which scr'aper vanes I'll rotating within the sleeve memher l o! theroter l00. the roter l00 anal runner l50 should be driven in the driveratio of nine to eight. For example. assuming that the throwing roterI00 has a blade tip diameter sufilclent to develop the desired abrasiVeblast when rotat- Ing at 2250 R. P. M. the control runner I50 includingthe scraper vanes I'll would then be rotated at approximately 2000 R. P.M. 'I'his drive ratio may be maintained as heretofore'explalned byproviding the drive shafts I3 and 5I within a connected driving gearhaving the proper drive ratio. The abrasive supplied to the feedcontainer I5l is thrown by centrifugal force out through the spaceddischarge ports I 10 thereof into the path of rotation 01 the vanes l28and thence .into the abrasive recelv'lng pockets i2'l irom which theabrasive roll5 across the inclined inv terior surface l2'l' of thetubular sleeve member l20 while resting on this interior surface. toform spaced ridges or piles ol abrasive. Whil the scraper vanes I'llrotate in the same direction of rotation as' the port openings l and thethrowing blades b. they rotate at less velocity as above indlcated, sothat the rear surface of each scraper vane I'll will drag over thedischarge ports l25 m. a predetermined clockdial position of rotation ofthe throwing roter I00, causing the .abrasive to discharge l'rom thedischarge ports I25 onto the throwing blades b from which it is thrownat an abradlng velocity. The lower end I'l2 o1 each scraper vane lll ispositioned closely adjacent the lnSlde suriace l2'l' o! the tubularsleeve member I20 and is further inclined on a blasse as to scrapeabrasive into the discharge port l25 over substantially the full axialwidth of the discharge port l25.

Adjustments can be made so that the abrasive dlscharged from thethrowing roter l00 will. be fired' in any desired clockdial direction.Thls ls eflected by proper rotative adjustment of the discharge passagesl25 in the rotor container l20 with respect to the scraper vanes I'llassoclagted wlish the control runner I50. This discharge ad- .iustmentcan be advantageously effected by re settlng the gear 85 in the gear box82.

It will be appreciated that the throwing roter inay be made ln anydesired dlameter and may be rotated als any desired speed, the c ontrolrunner being rotatecl at a corresponding speed ratio determined by therelative number of allsports can be so acljusted that abrasive isscraped into the discharge portsof the runner at an v clesired clockdialposition dluing rotatlon, by mterely adjusting the position of thescraper vanes with respect to the discharge ports of the roter.

It will be further appreciated that in the several illustratedembocliments of thig invention, the throwing rotor may be providecl withany desired number cf throwing blades or discharge ports. ancl a highdegree of directional control can be continuously malntained byproviding a nontrol runner having either a greater or lesser number ofscraper vanes, preferably providing the control runner with either onemore or one less scraper vane than abrasive discharge ports provided inthe throwing roter. if abraslve firing from a Single selected clockdialposition is deslred. The abrasive may be fired from an abrasive roter inany desired clockdial direction by a. proper mathematical adjustment ofthe control runner with respect to the throwing rotor.

Assuming, l'or example, that a throwlng rotor ls provided with eightequally spaced discharge' passages or blades.and the control runner isprovlcled with nine equally spaced scraper vanes, as shown in Flgs. 5and 6, and that lt is desired to shift the direction of discharge from anormally downward or six o'clock position to a normally sideways orthree o'clock position, with the roter and ru'nner 1otating clockwlse.This control adjustment can be effected by rotating the control runnerl50, as shown in Figs.l 5 and 6', so as to bring one cf the scrapervanes I'll thereofinto a pcsitio n whereby it would scrape abrasive intoone cf the dlscharge ports l25 of the tubular sleeve member of theroter, at approximately the nine o'clock position. 'Ihis would requlrer0tation of the control runner 150 a distance of approximately 10counterclockwise from its position shown in Figs. 5 and 6 where therunner anti rotor parts are shown in position to discharge abrasivethrough a discharge port I25 at the twelve o'clock position. Thisassumes, cf course, that the roter blades are of such length that whenthe abrasive ismovecl out to the inner ends there'of at approximatelythe nine o'clock posi tion, lt will discharge at approximately the threeo'clock position. The am through-which the abrasive is carried by theroter blades after be- It mayat times be desirqd to clean castings,-

- forgings, bars and sheets which are positioned on charge passagewaysorblades in the rotor with respect to the scraper vanes 011 the runner.The rotor and runner are rotatedat speeds which are in inverse ratio to'the number of their discharge opposite sides of the throwing rotdr. .Myimproved centrifugal abrasive throwing machine.

may be constructed and deslgned to acbomplish thls result by providingthe machine With a coutrol runner having equally space d abrasivescraper vanes or passages either two more or two less in number than theabrasive discharg e ports in the throwing roter. The control runner andthrowing roter are then rotated in timed relation so that two oppositescraper vanes in the control runner will scrape over two opposltedischarge placed when worn.

' pattern on the target.

i'ts in the throwing roter at opposed clockdial positions duringrotatibn thereof.

Tims it will be appreciated that accurate and controlled flring in on edirection only or in two or more predetermined directions from the samemachine can be obtained by providing the cantrol runner and throwingroter with a proper number of scraper vanes and discharge ports androtating the runner and roter at speeds which are in inverse ratio tothe number of scraper vanes and discharge ports therein. Upblast o1downblast, or both upblast and downblast a three o'clock side blast or anine o'clock side blast or both a. three oclock and a nine o'clock sideblast, may be obtained with a ma chine constructed as above described.

'Ihe throwing roter may be of any desirecl diameter, preferabfy rangingfrcm nine to thirty inches, and the throwing blades or passages of thethrowing roter may be of any desired radial length and, if desired, maybe of such length as 1:0 extend ciose 120 the axis of rotaoion,providing 1 on the-control runner and the robor sleeve may becorrespondingly reduced, with greater wear concentrated on the throwingb1ades of the roter, which ma.y be made removable and replaceable. If ththrowing blades of the throWing rotor are of relatively short radiallength with a corresponding increase in diametriu size of the controlrunner, the control runner and particuiarly the scraper vanes thereofwill then receive some wear, and these vanes may be made removable andreplaceable as is obvious to those skilled in the art.

The abrasive receives its final abrading velocity from th advancingfaces of the rotor blade5or throwing surfaces thereof, which arepreferably made removable so that; these parts can be ro- The parts ofthe machine which receive tensile strains and shoc ks may be made of ahigh grade steel, and the parts subjected to wear may be made of asuitable wear resisting metal.

One of the marked advantages of this machine is that an impingementpattern of almost any desired width may be obtained. ThiS desirableresult is accomplished by reason of the fa.ct that the scraper vanes ofthe control runner are arranged on a biasso that abrasive is scrapedover substantially the entire width of the dis-' charge ports in thethrowing roter: A substantz'ally uniform concemation of the abrasive isobtained throughout the impingement pattern. The longitudinal length ofthe impingement pattern may be reguiated as riesired by varying theperipheral length of the discharge ports in the throwing rotor. A highlysatisfactory degree of directional firing of th thrown abrasive may beobtained, and the impingement pattern nicely defined both as 130 itslength and its breadth. 'I'he abrasive is distributed unifdrmly oversubstantially the entire width of the rotor blades, producing moreuniform wear on each of these parts with a resulting full widthimpingement The length of the impingement pattern on the target can beeasily fixed and determined by varying the peripheral length of thedischarge ports in the throwing rotor.

It is understood that where the term abrasive is hereit1 used, it isinte'nded 130 refer to steel shot or grit, quartz sand, or ot;hergranular material commoniy used in the blast cleaning of castings,forgings, bars, sheebs and Iike metallic materials, to reniove encrustedmolding sand, irr egular projections and scale 1'rom the surfacethereof.

Whiie certain novel features of the invention have been disclosed andare pointed out in the annexed claims, it will be understood thatvarious omissions, substitutions and changes may be made by thoseskilled in the art without departing from the spirit 01 the invention.

What is claimed is:

1. A centrifugal abrasive blasting machine operab1e to throw aconcentrated stream of abrasive over a predetermined Iimited areincluding, a. rotatably mounted roter having a plurality of equal1yspaced abrasive discharge passages whose inner ends are separated byarcuate s haped abrasive receiving surfaces facing inwardly and spacedfrom the axis of rotation thereof whereby said surfaces define a pentral space, means fordepositing abrasive tifi said arcuate surfaces, a

rotatably mounted control runner positioned within saidoentral spacehaving a piuraiity of equally spaced abrasive scraper vanes differing innumber from the number of discharge passages in sai-d roter, the outerends of said scraper vanes being positioned to 6ngage the abrasive onsaid arcuate surfaces during rotation cf said runner, and driving meansoperable to rotate said roter and runner in timed r'elation and atspeeds which are in inverse ratio the numbet of discharge passages andabrasivia scraper vanes' in said roter -and runner respectively so as tomove the abrasive engaged by the successive vanes in said runner intoabrasive discharging position with respect to the successive passageserable to throw a concentrated stream of abrasive over a predetermined1imited are including, a ro-.

tatabiy mounted rotor having aplurality cf equally spa'ced abrasivedischarge passages Whose inner ends are separated. by arcuate-shapedabrasive receiving surfaces facing inwardly and spaced from the axis ofrotation thereof whereby said surfaces define a centra1 spac e means fordepositing abrasive on said arcuate surfaces, a rotatahiy mountedcontro1 runner positioned within said centrai space having a pluralityof equally spaced abrasive scraping means differing in number from thenumber of discharge passages in th throwing roter, the outer ends -ofsaid scraping means being positioned to engage the abrasive on saidarcuate 'surfaces during rotatiun of said runner, and means for rotatingsaid roter and runner in timed relation and at speeds which are ininverse ratio to the number of discharge passages and abrasive scrapingmeans in said' rotor and runner respectively so as to move thesuccessive means of said runner into abra)sive discharging position withrespect to the suczcessive passages of said rotor at a predeterminkedclockdial position during rotation.

3. A centriiugal abrasive blasting machin operabie to throw aconcentrated stream of abrasive over a pred etermihed 1imited areinclucling, a

.rotatably mounted rotor including a. generaily mounted control runnerpositioneci within sa.id central space having a plurality cf equa.llyspaced abraslve moving vanes differirig in number Ioy one from thenumber cf discharge passages in th throwing roter, the unter end s ofsaid vones having a plurality of throwing elements supported by sa.idside wall member. ea.ch of said throwbeim; positioned to engage theabmsive 021 saioi arcuate suriaces during rotation bi s aid runner, analmeans for rotating sa.id rotor and runner in tim ed relationuhip and atspeeds which am in inverse ratio 120 the number of discharge passa.gesand. abrasive movinz vanes in saioi rotor and runner respectively so asto move the successive vanes cf sah! runner into abrasive dischargingposition wlth respect to the successive passages of said roter a.t apredetermi'ned clockdiai position during rotaision.

4. A centrifugill abrasive biasting maohine operable to throw twooppositely directed concentrated streams of abrasive each dis'charg'edover a predetexmined limitecl arc including, a rotatably mounted roterhaving a..plurality of equally spaced abrasive discharge passages whoseinner ends are separated by arcuate-shaped abrasive recelving surtacestacing inwardly and spaced from the axis 01 rotation thereot definlng acentral space, means for depositing abrasive on Sa'id arcuate surfaces.a. rotatably mounted control runner positioned within sald central spacehaving. a pluraiity of equally spaced abrasive moving vanes difiering innumber by twb from th'e number.of discharge passages in the throwingroter,

the unter ends of saiii vanes being positioned to engage the abrasive011 said arcuirte surfaces during' rotation 02 said runner, and meansfor rotating said roter und runner in timed relation ing elements havingan abrasive discha.rge port adjacent the inner end thereof which poriasa.re separated by inwardly facing arcuai;e-shaped abrasive receivingsu1faces. s. controi runner com- 4 prising a rotatably mounted tubularmember having openings therein through' whichabrasiveis supplied tosaicl arcuate surfaces, a plurality of equally spaced vanes fixed torotate wi th said tubuiar member, und diflering in number' from thedischarg ports in said roter, means for supplying abmsive to the tubularmember of sald runner, Bnd drivihg means operable to rotate said rotoirand runner in timed relation and a.t speeds which are m inverse ratio tothe number of discharge ports and abrasive moving vanes in said roterand runner respectively so as to sweep the vanes of said runner intoabrasivedischarging position. with respect to said roter ports at apredetermin ed clockdial position during rotation.

7. A centrifugal blasting machin operable to throw a concentrated streamof abrasive over a predetermined iimited am including, a. rotorcomprisinga rotatably mounted side wail member and an overhanging rlmsupport'ed by said side wall member having equally spaced dischargeports therein, a. control runner fitting within said v rlm comprising aplurality o1! ec1ually spaced am! at speeds which are in inverse ratioto the number o1 discharge bassages and vanes in :said roter and runnerrespectively so as to move the sucpessive vanes o1! said runner intoopposite abrasive discharglng positions with respect to the successivepassages 01 said rotor at predetermined opposite clockdial positionsduring rotation.

5. A centrifugal abrasiv biasting machine operabie to throw aconcentrated stream of abrasive over a predctermined limited amincluding. a rotatably monted roter having a pl'uraiity ot equallyspaced abrasive discharge pass ages which are separated by inwardlyi'acing arcuate-shaped abrasive receiving surifaces, means fordepositing abrasive on said arcuate surfaces. a rota.tably mounteacontrol runner ha.ving a plurality of equally spaced abrasive movlngvanes ditfering in number from the discharge passages of the throwingroter, sald runner having its axis of rotation concentric with the axisof rotatioh of ;said rotor with the unter ends 'ot the abrasive movingvanes of -1:he runner positioned adjacen't the inner ends 01 butdiagonally arranged with resbect to the passages in the rotor, the unter(ands o! sa.id vanes being positioned to enga.ge the abrasive on s aidarcuate surfaces during rotation o1 said runner, und driving meansoperable to rotate said roter and runner in timed relation 811d atspeeds whlch are in inverse ratio to the number of dischargdpassages-and abrasive movi'ng vanes insaid roter und runner respectivelyso as 1:0 move the discharge ends of th e abrasive moving vanes o! saidrunner into abra.sive ejectlng position with respect to the inner ends013 the successive passages in said roter at a predetermined (flockdialposition during rotation. 6. A centrifugal biasting machine opera.ble

throw a concentrat'ed stream of abrasive over a,

predetermined iimited arc including, a rotor comrising a rotatablymounted side wali member abrasive moving vanes whose axis of rotation isconcentric with the axis of rotation cf said rotor said runner vanesdiffering in number from the discharge ports in said roter rim, 'meansfor supplying abrasive to the inner surface of saici overhanging rim,und means for rotating said roter and runner in timed relation und abspeeds which' are in inverse ratio to the number ot dischaxge ports andvanes in said roter a.nd runner 'respectively so as'to move thesuccssive vanes 01 said runner into abrasive discharging position withrespect to the successive discharge ports of said roter at apredetermined clockdial position during rotation.

8. A centrifugal blasting machine operable to throw a. concentratedstream 01 abrdsive over a predetermined limited arc including, arotatably mounted shaft a. roter supported on said straft,

said rotor having equally spaced abrasive discharge passages separatedby inwardly Iacing arcuate-shaped abrasive receiving surface's means fordepositing abra.sive on said arcuate surfaces,

a second shaft having its a.xis 01 rotation substantialiy conceritricwith the axls o1 rotation of saicl first sh'a.ft, a control runnermountecl on said second shaft having equally spacedabrasive moving vnnesdiflering in number from the number of discharge passatges in seidroter. the ouber ends ot said vanes be1ng positioned to'engage theabrasive on said arcuate surtaces dring rotation cf said runner, unddrlving mechanism operably .connected to said shafts whereby said rotoram! runner can be rotated in timed telation und ai;

sp'eeds whichare in inverse ratio the number the axis cf rotationthereof whereby said surface3 define a central space, means fordeposlting abrasive on said arcuate surfaces, a rotatably mounted shaftfixed to said rotor a control runner positionecl within said centralspaoe having equally spaced abrasive moving vanes therein differing innumber from the number of discharge passages in said rotor, the outerends of said vanes being positioned to engage the abrasive; on saidarcuate surfaces during rotation of said runner a second rotatablymounted shait fixed to said runner having its axis of rotationconoentric with the axis of rotation of said rotor sh'aft, a drivepulley adaptecl to be connected to a power source. and. mechariismoperably connecting said 1 pulley to said shafts whereby said shafts maybe rotated in timed relation and a1; speeds which are in inverse ratioto the number o1 discharge passages und abrasive moving vanes in saidrtor arm runner respectively so as to move the successive vanes of saidrunner into disoharging alignment with successive passages in said rotra1: a predetermined clockdial position during rotation.

10. A centrifugal abrasivd blasting machine operable to throw twooppositely directed concentrated streams of abrasive each dischargingover a predetermined limited arc including, a rotatably mounted rotorhaving an even number of equally spaced abrasive discharge passagestherein separated by inwardly facing arcuate-shaped abrasive receivingsurfaces spaced from theaxis oi rotation thereof whereby saidsurfacesdefine a central space, means ior depositing abrasive on said arcuatesurfaces, a rotatably mounted con- 1 tro1 runner positioned within saidcentral space having an even number 015 equally spaced abrasive movingvanes two 1ess in number than the number of discharge passages in thethrowing rotbr, the inner ends of said vanes being positioned to engagethe abrasive on said arcuate surfaces during rotation of said runner,and means for rotating said roter and runner in timed relation und a1:speeds which are in inverse ratio to th'e number o1 discharge passagesand vanes in said roter and runner respectively so as 130 move thesuccessive vanes of said runner lnto opposite abrasive dischargingpositions with respect to the successive passages o1 said roter atWedetermined opposite tation. h

11. A centrifugal abrasive blasting machine operative to throw aconcentrated stream of abraclockclial positions during rosive over apredetermined limited arc including, a

rotatably mounted roter having a plurality of equally spacedcircumferentially extending segments presenting inwardly facingarcuate-shaped abrasive receiving' surfaces and defining abrasivedischarge passages therebetween, means for depositing abrasive on saidarcuate surfaces, a rotatably mounted runner having a plurality ofequally spaced radially extending abrasive moving vanes differing innumber from the number of discharge passages in said rotor, said runnerha.ving its axis of rotation concentric with' the axis of rotation ofsaid rotor with the outer end of the abrasive moving vanes of the runnerpositioned adjacent the inner ends of the discharge pas'sages in.theroter, and drivlng means operable to rotate said roten and runner intimed relation and at speeds which are in inverse ratio to the number ofdischarg e passages and abrasive moving vanes in said roter and runnerrespectively so as to move the outer ends o1 said runner vanes intodischarging alignment with the successive passages in said roter ab apredetermined clockdial posltion during rotation.

12. A centxifugal abrasive blasting mach'ine opera.ble to throw aconcentrated stream of abfasive over a predetermined limited arcincluding, a rotatably mounted rotor having a plurality of equallyspaced circumferentially extending segments defining abrasive dischargepassages therebetween, a. rotatably mounted runner having a. pluralityof equally spaced radiating vanes difi'ering in numberfrom the number ofdischarg passages in said roter, said runner having its axis of rotationconcentric with the axis of rotation of said roter, with the outer endsof its vanes positioned acljacent the inner ends 015 the passages in theroter, means for depositing abrasive on the inner facing surface of saidsegments and inverse ratio to the number of discharge passages and vanesin said rotorand runner respectively so as to move the outer ends ofsuccessive runner vanes into discharging alignment with successive roterpassages at a predetermined clockdial positiot1 during rotation.

13. A centrifugl blasting machine operable to throw a concentratedstream of abrasive over a predetermined limited arc including, arotatably mounted rotor having a plurality of equally spacedcircumferentially ex tending segments defining abrasive dischargep9ssages therebetween, said segments each having a generally arcuateshaped inner end defining therebetween a central space of "generallycircular form, a rotatably mounted runner positioned within said centralspace havinga plurality of equally spaced genera 1ly radially extendingabrasive moving vanes difiering in number from the number of dischargepassages in said roter, means for supplying abrasive to said runnervanes, and drivir'xg nieans operable to rotate said rotor and runner intimed relation and at speeds which are in in,-

' vers e ratio to the number of discharge passages vanes intodisoharging alignment With successive rotor passages at a predeterminedclockdial position during rotation. 1

14. A centrifugal .blasting machine operable to throw a concentra'gedstream of abrasive over a predetbrmined limiting arc including, arotatably mounted rotor having a plur'ality of equally spaced radiallyarranged throwing blades extending inwardly short of the axis ofrotation of said rotor to define a. central space, a tubular sloeveextending 1nto said space fixed to rotate with said blades, said sleevehaving equall y spaced abrasive discharge ports in th'e tubular sideWall thereof adjacent the inner ends of said blades, a rotatablyniounted control runner fitting within said sleeve comprising aplurality of equally spaced abrasive moving vanes difiering in numberfrom the number of discharg ports in said rotor sleeve, means forsupplying abrasive to said runner vanes, and driving means operable torotate said roter and runner in timed relation and deflnlng a centra.lspace, artubular sleeve having' a discharge port for each o! said bladesrotatlng with sa1d blades and extending into said central space, acontrol runner fittlng wlthin seid rotor sleeve, seid runner comprlsingequally spaced abrasive moving vanes extending lnwardly short of theaxiso1 rotation of seid runner to deflne a. central space, seid runner vanesdlflerlng in number from the number o1 discharge ports m sald roter,means fo1 supplying abraslve to the central space in seid runner, anddriving means opera.ble to rotate sald rotor and runner in timedrelation anti at speeds which are in inverse ratio to the numberofdlscharge ports am! abraslve movlng vanes in seid roter and runnerrespectively so a.s to move succ'esslve runner vanes into dlscharglngalignment with successlve rotor ports at a. predetermined clockdialposltion during rotatlon.

16. A centrifugal blasting machlne opera.ble to throw a concentratedstream of abrasive over a predeber'mined llmited am including. arotata.bly mounted rotor having a. plurallty of equally spaced radlallyextending throwing blades exspaced abraslve passages in thetubular sideWall thereof adja.cent the lnner ends o! seid blades, a. rotattablymounted control runner fitting within seid sleeve comprlsing a tubularmember having equally spaced dlscharge ports in the tubular slde wallthereof, vanes flxed to sa1d roter sleeve for plllng abra.slve recelvedfrom the discharse ports of sa1d tubular runner member between thedischarge passages' of seid roter sleeve, abraslve,

scraper va.nes fixed to rotate with seid tubular umher member ha.vingthe unter ends there-ot posltloned to sweep th'e 'abrasive plles intothe discharge passages of seid roter sleeve, said vanes difiering innumber from the number of discharge 'passages in seid roter sleeve,means for supplylng abraslve to seid tublar runner memher, anti drivlngmeans operable to rotate seid roter and runner in time relation und atspeeds which are in lnverse ratio to the number of discharge ports a.ndvanes in seid rotor and runner respectively"so es to move succes'slverunner vanes into dlscharging allgnment with successive rotor passageset a predetermlned clockdial position during rota.tion.

CHESTER E. UNG'ER.

